One of the study's co-authors, Dalhousie University biology professor Boris Worm, tells The Associated Press that "we are really fairly ignorant of the complexity and colorfulness of this amazing planet. ... We need to expose more people to those wonders. It really makes you feel differently about this place we inhabit."

Now, if 85 percent of all species haven't been discovered, how did the scientists come up with their numbers?

The AP explains it this way: "Worm and Camilo Mora of the University of Hawaii used complex mathematical models and the pace of discoveries of not only species, but of higher classifications such as family to come up with their estimate."

As National Geographic points out, however, some scientists believe the researchers' reliance on "linear regression" instead of "ordinal regression" was a mistake. (Please, anyone who can explain those terms and what the argument is about, feel free to try to do so in the comments thread.)

Regardless, if the 8.7 million estimate is even close, "we could spend the next 400 or 500 years trying to document the species that actually inhabit our planet," Encyclopedia of Life executive director Erick Mata tells the AP.